Underreamer



N A W s F UNDERREAMER '2 sheets-sheet 1 Filed NOV. 25, 1936 l f IlINVENTOR. f-Pe d Swan Patented Mar. 15, 1938 UNITED shares FATENT OFFICE12 Claims.

The present invention consists of an underreamer especially adapted foruse in oil wells and is an improvement on patents previously granted tome in this art, especially my Patents Numbers 1,372,917 and 1,578,482,as well as Swan Patent No. 997,718. While the Swan underreamers, nowextensively used in this art, are effective for reaming a hole ofgreater diameter than the interior of the casing regardless of thestrata formation of the earth, I have found that a more eiicient tool isprovided by following the teaching of the present invention, a preferredform of which is illustrated in the accompanying drawings.

It is within the contemplation of this invention to retain cuttersoperated intoan expansive or operating position by an upwardly movingspring rod but the `mounting of the cutters has been modiiedito changethe angularity of the cutters when in use to positively effect operationof the cutters through any of the variety of earth formation, whetherhard or soit, with minimum wear on the tool and with a completeelimination of tool fracture, rupture or breakage, notwithstanding thefact that the working ends of the cutter may impinge against solidformation immediately on leaving the casing, the angularity of thecutters positively preventing their collapse when engaged with rock orlike solid formations.

It is a further object of this'invention to provide expansible cutters,the work engaging terminals of which are free to permit contact of thecomplete terminals with the work, the conformation of the terminals andthe angularity of cutter bodies permitting the wall to be attacked fromabove, after initial penetration of the wall surface, as well as at theside to more expeditiously and more effectively break down the wall,during which operation the line of stress is on the long axes of thecutters.

Another object of the invention is to provide a cross bar which isautomatic in its operation to lock the spring rod and cutters togetherwhen the cutters are moved into an expanded position, 45 the bar beingloosely mounted in the spring rod and cutters and being freely removablewhen the cutters are in a` collapsed position. It is also within thecontemplation of the present invention to provide a detent, which isalso automatic in its operation,V to secure the cutters in a co1- lapsedposition, the detent being likewise automatically disengaged when thereamer is oper-V ated to permit the cutters to expand, the detent 55being of peculiar design to assure its Velective operation over a longperiod of time without replacement.

Other objects of the invention will be apparent from the followingdescription of the present preferred form of the invention, wherein:- 5

Fig; l is a vertical sectional View of an underreamer constructed inaccordance with the present invention illustrating its application,showing the cutters in an expanded or operative position.

Fig. 2 is a similar view showing the cutters in a collapsed positionwithin the confines of the casing. f

Y Fig. 3 is a fragmentary detail enlarged view of the reamer bodyshowing the spring rod and detent in side elevation illustrating themanner in which the rod is held in a iixed position by the detent.

Fig. 4 is a detail fragmentary perspective view of one of the detents.20

Fig. 5 is a side elevational view, partly in section, of a reamer bodyconstructed in accordance with this invention.

VFig. 6 is an end elevational view of one of the cutters. Y

Fig. 7 is a fragmentary elevational viewof the reamer body showing thecutters mounted therein, the latter being in collapsed position.

Fig. 8 is a side Yelevational View of one of the cutters;V Fig. 9 is anelevational View of the spring rod Y constructed in accordance with thepresent invention.

' Fig. 10V is a side elevational view of an underreamer constructed inaccordance with this invention showing the means of thepresent inventionused for collapsing the cutters.

, Fig. 11 is a perspective view of the locking bar, and

Fig. 12 is a cross sectional view shown on the line IZ--IZ of Fig. 10,'looking in the direction of the arrows, illustrating the manner ofmounting the releasing bar through the reamer body, above the springrod. H

In the drawings for purpose of illustration, a portion of a Well casingi3 is shown which is of standard construction, and is mounted in theearth'in a manner well known in the art.

The tool constructed in accordance with the present ,invention includesa reamer body lli, the

, lowerV terminal of which is provided with recesses i5 in the sidesthereof, the portions of the terminals below said recesses beingrounded, as indicated atl I6. The inner Wall of each of. the

terminals I6 is rabbeted out to provide cutter 55 engaging recesses I'l.The reamer body I4 is provided with the usual bore I8, which isconstricted, as indicated at I9, just above the rounded terminal I 6.The wall of the reamer body is provided with longitudinal slots in theopposite sides of the body, the slots being preferably formed at a pointappreciably above the constricted bore I9.

Mounted for movement in the bore I 8 is a spring rod 2|, the upper endof which is formed to provide a head 22 in which a kerf 23 is formed.The lower end 24 of the rod is enlarged, the jointure of the rod properand the enlargement lseing formed to provide bevelled shoulders 25. Thelower end ofthe enlargement 24 is tapered to provide a truncated coneshape 'terminal 26. The enlarged end 24 of the rod is provided with alongitudinal slot 2'I which is adapted for the reception of a cross bar28, the free ends of which project beyond the rod and engagecomplemental openings 29 formed in cutters 30. Preferably, the cross bar28 is of the configuration shown in Fig. 1l of the drawings and includesflared terminals 3|. This contour of cross bar permits the latter to befreely engaged with and disengaged from the cutters and spring rod.However, when the cutters 38 are in an expanded position, as shown inFig. 1 of the drawings, the inclined free faces of the ared ends 3l bearagainst the correspondingly formed upper walls of the openings 29 of thecutters, while the lower faces of said flared ends bear against thelower walls of the cutters thereby positively locking the cutters fromdisplacement and also preventing the cross bar from any appreciablelongitudinal movement of the cross bar. If perchance the cross barshould move lengthwise, in either direction during the operation of thetool, the conformation of the flared ends and the walls of. the cuttersautomatically returns the cross bar to a central or normal position, asshown in Fig. 1.

Each of the cutters 3U is provided at its upper or inner end with a boss32 which complements and is movably engaged in one of the recesses I1 inthe lower terminal of the reamer body. The upper or inner wall of eachcutter is formed to provide an abrupt shoulder 33 which complements andis adapted for engagement in one of the recesses I5. By this formationthe support of each cutter when in the expanded position shown in Fig. 1of the drawings is on the line of impact ofthe cutter, the line ofimpact carrying substantially through the top of the axis of the cutterand the solid walls of the reamer body at diametrically opposite points.By this construction, excessive outward or expansive movement of thecutters is prevented, yet the free ends of the cutters are in no wayrestrained or housed leaving them free for engagement with the work.Preferably, the working terminal of the cutter is of substantiallyinverted V-shape configuration, as indicated at 34, it being preferredto slightly elongate the inner or trailing toothed portion of eachcutter. The outer or entering toothed portion of each cutter, which isrelatively shorter, is adapted for penetration in the wall, but isoperated so as to rst bite into the wall surface and then tear down thesub-strata of earth regardless of its formation, The inner or trailingtooth of each cutter serves as a guide and as shown in Fig. 1 of thedrawings normally remains slightly spaced from the wall being torn down.

In order to expand the cutters 30, as shown in Fig. 1 of the drawings, Iprovide the rod 2I with a spring 35, one end of the spring bearingagainst the head 22 while the opposite end bears against a permanentpart of the reamer body just above the constricted portion I9 of thebore. Consequently pressure is exerted upwardly on the rod 2i whichcorrespondingly urges the cross bar 28 upwardly and throws the lower orworking ends of. the cutters outwardly into expanded position. Thisangularity of the cutters positively insures engagement of the outertoothed portions of the cutters with the wall and likewise preventscasual folding or collapsing of the cutters when solid formations areencountered during the reaming operation.

While the reamer is being passed through the casing, it is desired thatthe cutters be held in a collapsed or inoperative position and for thispurpose I provide a detent 3S which is mounted through the wall of thereamer body and is adapted for engagement with one of the bevelledshoulders of the rod. Preferably, the rod engaging end of the detent issquared to provide a plurality of, flat faces 37, each of which isbevelled to conform to the contour of the shoulders 25 and anyone ofwhich may be engaged with said shoulders. Consequently, as one of thesquare faces of the detent wears, the detent may be rotated to bringanother face into use. Correspondingly, when one of the shoulders 25begins to show wear, the rod 2| may be turned so as to bring the othershoulder into play. The detent is provided on its outer end with a head38 which serves as an abutment for one end of a spring 39, the upper endof the spring bearing against the reamer body around the opening in thelatter through which the detent moves. Consequently the detent isnormally held disengaged from the rod 2 I. When the detent is in adisengaged position, it is retained from displacement by a screw cap 4Gmounted in the .reamer body outside of the detent head 38. v When it isdesired to collapse the cutter heads, downward pressure is exerted onthe rod 2I in a manner hereinafter set forth, and at the same timepressure is placed on the head 38 of the detent by a suitable implement.As soon as the rod 2| has been depressed to the point where one of theshoulders 25 crosses said detent, the latter will automatically moveinto position above the shoulder as shown in Fig. 3. By releasingpressure on the rod 2l the detent and rod are frictionally locked in anapparent manner. When in a collapsed position the cross bar 28 is freeto be engaged with or disengaged from the cutters and spring rod. Toprevent accidental displacement of the cross bar while the tool is beingpassed through the casing, I provide the cutter heads with grooves 4Iand the flared ends of the cross head 28 with openings which are adaptedfor engagement by a strand of wire 4I. The wire is secured and this issufficient tc hold the cutter heads against the lower end of the springrod, as well as preventing the cross bar 28 from displacement. As soonas the lower end of, the tool leaves the casing and it is desired toexpand the cutters, contact is made with the tool in the usual manner,the impact of which is sufcient to move the rod 2I slightly downwardlywhich causes automatic release of the detent 36 thereby permitting thecutters to break the strand of wire surrounding the same and to expandinto operative position.

A preferred form of means of depressing the rod 2l, which is commonlyreferred to in field work as a pull down, is illustrated in Figs. 10 and12 of the drawings. This depressing means or pull down includes a bar42, which is adapt- Ato ed to be engaged through thel slots 20 of thereamer body and withthe kerf .23 of the spring rod 2l. One of the barsis engaged through a link with one end of. a U-shaped frame 43, theupper end of said frame being engaged with a. recess d4 formed intheupper margin of the bar 42. The U-shaped frame extendsappreciablybelow the tool and is adaptedto' be engaged by a chain or other suitablemeans 45 anchored to a support. When the tool is elevated by hoistingmeans commonly employed in the art, the spring rod is caused to bedepressed against the resistance of the spring 35 until the detent 36locks over one of the shoulders 25 in a manner already described.Following this operation the depressing means or pull down may bedisengaged in an apparent manner.

While I have herein described a preferred form of the invention which Ihave found in actual practice to perform the functions attributed to it,I am nevertheless aware that various changes may be made therein withinthe scope of the claims herewith appended.

What is claimed is:

1. An underreamer for oil wells including a reamer body equipped withcutters one end of each of which is pivotally mounted in a terminal ofthe body and movable to project the free ends of the cutters outwardlybeyond the plane of the reamer body and completely below the terminal ofsaid body, the Vreamer body engaging ends of the cutters having abruptshoulders for engagement in complemental recesses formed in the reamerbody, said recesses being formed in the body in a plane above thepivotal axes of. the cutters and being disposed on such an inclinationfrom the horizontal as to provide cutter supports in the direction ofthe normal thrust of the cutters.

2. An underreamer for oil wells including a reamer body equipped withcutters pivotally mounted in the lowest terminal of the body, thecutters being movable to permit expansion of their free ends outwardlyat an angle to the body axis, the upper ends of the cutters engaging thelower terminal of the reamer body above the pivotal axes of the cuttersin a plane normal to the cutter angle, whereby impact on the latter willbe absorbed by the central portion of the reamer body in the directionof the normal thrust.

3. An underreamer for wells including a reamer body equipped withcutters pivotally mounted in its lowest end, the work engaging terminalof each of. which is of substantially inn verted V-shape to provide apair of obtusely related teeth, said cutters being expansible todisbody, means mounted in said body `for expanding Y the cuttersincluding a spring rod anda cross bar, said cross bar being looselymounted in the spring rod and cutters and removable therefrom when thecutters are collapsed, the cross bar having end portions so shaped as toautomaticallylock the cutters from displacement when in expandedposition.

5. An underreamer for wells including a reamer body provided withopposed longitudinal slots, cutters mounted in said body, means mountedin said body for expanding the cutters including a spring rod providedwith a slotted head, and means engageable in said slots for depressingsaid rod'to collapse the cutters including a bar engageable through the'reamer body and in the slotted head and downwardly urged pressureexerting means engaged with the ends of, said bar.

6. An underreamer for wells including a reamer body, cutters pivotallymounted in said body the outer faces of which are grooved, means forexpanding the cutters including a spring rod and a cross bar, said crossbar being loosely mounted in the spring rod and cutters and removabletherefrom Ywhen the cutters are collapsed, the ends of said bar beingperforated in the plane of the cutter grooves, and means engageablethrough said perforations and with said grooves to prevent displacementof said bar and the cutters when the latter are collapsed.

7. An underreamer for wells including a reamer body provided withopposed longitudinal slots, a pair of cutters pivotally mounted in anend of said body and provided with opposed openings, a spring-pressedrod slidable in said body provided with an opening adjacent the lowerend thereof, a bar loosely disposed in said openings of. said cuttersand the opening in said rod, a head on the upper end of said rod, andmeans engageable with said head through said slots to move said cuttersto collapsed position.

8. An underreamer for Wells including a reamer body provided withopposed longitudinal slots, a pair of cutters pivotally mounted in anend of said body and provided with opposed openings, a spring-pressedrod slidable in said body provided with an opening adjacent the lowerend thereof, a shoulder carried by said rod intermediate the endsthereof, a spring-pressed detent carried by said body and engageablewith said shoulder for holding the cutters in collapsed position', andmeans engageable with said rod through said slots in said body formoving said cutters to Vcollapsed position.

9. An underreamer for wells including a reamer body, a pair of cutterspivotally mounted in an end of said body provided with grooves in theouter surfaces thereof, spring-pressed means carried by said bodyengaging said cutters for moving said cutters to extended position, andfrangible means engageable in said grooves for holding said cutters incollapsed position.

10. VAn underreamer for wells including a reamer body, a pair of cutterspivotally mounted in an end of said body provided with grooves in theouter surfaces thereof, a bar loosely engaging said cutters and disposedtransversely of said body, spring-pressed means carried by said bodyengaging said bar for moving said cutters to extended position, said barhaving a notch in each end thereof adapted to aline with the grooves insaid cutters, and frangible means engageable in said grooves and saidnotches for holding said cutters in collapsed position WhileVsirrulltaneously holding said bar from lateral movement relative tosaid cutters when said cutters are in collapsed position.

1l. An underreamer for Wells including a reamer body, cutters pivotallymounted in said body the outer faces of which are grooved, means forexpanding the cutters including a spring rod and a cross bar, said crossbar being loosely mounted in the spring rod and cutters and removabletherefrom when the cutters are collapsed, the ends of said bar beingperforated in the plane of the cutter grooves, and rangible meansengageable through said perforations and with said grooves to preventdisplacement of said bar and the cutters until the latter are expanded.

12. An underreamer for wells including a reamer body, cutters mounted insaid body the outer faces of which cutters are grooved, means carried bysaid body for expanding the cutters, and frangiblemeans engageablethrough said rst means and with the cutter grooves to preventdisplacement of said first means and cutters until the latter areexpanded.

FRED SWAN.

